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Let x be the regular average rate, in miles per hour.
Under the severe condition, the average rate was (d-10) miles per hour.
The distance is the same:
2.5*x = 3*(x-10).
Simplify and solve:
2.5x = 3x - 30
30 = 3x - 2.5x
30 = 0.5x ===================> x = 30/0.5 = 60 milies per hour.
ANSWER. The distance is 60*2.5 = 150 miles.
Solved.
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